1. Field of the Invention
The disclosure relates generally to a piston reset apparatus, and more particularly to a piston reset apparatus for a multichip module
2. Description of the Background
All semiconductor chips do not necessarily generate the same level of heat or function satisfactorily at the same temperature. Thus, in MCM (multichip module) products, it is critical to position heat dissipating slugs properly with respect each chip. By properly positioning these slugs, heat may be appropriately dissipated, and chips may be maintained at proper functioning temperatures. A factor affecting the rate and amount of heat dissipated from a chip is the spacing between the chip and the heat slug.
A typical assembled MCM product consists of a hat that includes an array of pistons. Each of these pistons acts as a heat slug for a respective chip.
The height of some of the pistons is fixed in the hat, while others of the pistons are moveable and their heights may be adjusted to provide appropriate spacing for each respective chip. Sometimes there is a need to readjust the height of pistons. In order to allow the hat to be re-used, pistons must be first reset or repositioned near their initial positions prior to a being subjected to height adjustment.
The piston reset apparatus and operation presently used makes use of a plate that pushes equally on all movable pistons until the plate contacts the fixed pistons. For a variety of reasons, this apparatus and operation does not always provide proper positioning of the pistons for the MCM product subsequently assembled. As such, a more effective manner of resetting moveable pistons in an MCM would be desirable.